(A) Field of the Invention
This invention relates to novel reaction products produced by reacting 5-sulfoisophthalic acid with a water soluble copper salt. Fibers containing such a compound have improved ozone fading resistance when compared to corresponding fibers from which the compound has been omitted. The term "ozone fading" as used herein means color fading of dyed fibers resulting from the dyed fibers being exposed to ozone. The term "fiber" as used herein means spun yarn, continuous filament yarn or a monofilament.
(B) Description of the Prior Art
Polyamide carpet fibers, expecially those dyed with disperse dyes, exhibit considerable fading of color when exposed to low concentrations of ozone at high humidities. Such conditions occur along the Gulf Coastal regions and in areas of high atmospheric pollution.
It has been suggested in the prior art (U.S. Pat. No. 3,844,713) to use certain organic phosphites as antiozonants for polyamide fibers. However, relatively large amounts of the phosphites are required (i.e. 0.1 to 8%).
It was known to applicants prior to the present invention that the ozone fading resistance of polyamide fibers can be improved with the use of certain poly(copper phosphinates) as antiozonants. However, these antiozonants when present in carpet fibers often react with certain disperse dyes (e.g. disperse Red No. 55) during the dyeing of the carpets to produce an uneven coloration in the carpet piles which renders the carpets commercially unacceptable. Such uneven coloration is referred to as "splotching". Normally, carpets are dyed with disperse dyes at a neutral or slightly alkaline pH. While copper-containing fibers can be dyed with disperse dyes at a pH of 3.5 or less without causing splotching, at such pH the copper is leached from the fibers.
Accordingly, an object of this invention to provide effective additives (i.e. antiozonants) for improving the ozone fading resistance of polyamide fibers and also fibers containing such additives.
Another object of the invention is to provide antiozonants for polyamide fibers which when dyed with disperse dyes including disperse Red No. 55, do not cause splotching.